FR2494649A1

FR2494649A1 - Burglar alarm system for vehicle - uses fuel gauge sensor to provide warning of fuel level falls or changes due to tilt of car

Info

Publication number: FR2494649A1
Application number: FR8024857A
Authority: FR
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-11-24
Filing date: 1980-11-24
Publication date: 1982-05-28

Abstract

The burglar alarm system warns of either theft of fuel, or attempted removal of one of the wheels. The alarm makes use of the level of the fuel in the tank, as indicated by the sensor attached to the dashboard fuel indicator. When the car is parked, the sensor is connected to an electronic circuit which uses a current of a few milliamps. If the float moves, either because of loss of fuel, or the vehicle being tilted, the corresponding change is detected by the electronic circuit. This circuit provides an output of 5 watts in a warning signal which may be used to operate a relay turning on a light or sound warning signal. The signal is arranged to stop automatically after 30 seconds.

Description

Le présente invention a pour objet un dispositif électroniq destiné à la protection contre le vol des véhicules, de leurs roues et de leur carburant. The present invention relates to an electronic device intended for protection against theft of vehicles, their wheels and their fuel.

Ce dispositif actionne les avertisseurs ou tout autre signa sonore, lumineux ou radio pendant une trentaine de secondes aprè déclenchement et de fanon intermittente. This device activates the alarms or any other sound, light or radio signal for around thirty seconds after tripping and intermittent dewlap.

Le système se déclanche si le niveau de carburant baisse ou si son contenant subit une variation d'inclinaison. The system is triggered if the fuel level drops or the container undergoes a tilting variation.

Le système utilise pour cela jauge à flotteur du réservoir à carburant normalement monté par le constructeur. Le système s'intercale dans le circuit électrique entre la jauge et l'ind4- -cateur de niveau du tableau de bord. The system uses the float gauge for the fuel tank normally fitted by the manufacturer. The system is inserted in the electrical circuit between the gauge and the level indicator on the dashboard.

Lorsque le contact est mis, la liaison entre la jauge et l'indicateur-de niveau se fait normalement sans changement de caractéristiques. When the ignition is on, the connection between the gauge and the level indicator is normally made without changing characteristics.

Lorsque le contact est coupé, la jauge n'est plus en liaiso avec l'indicateur de niveau du tableau de bord mais avec le circuit électronique du système dans lequel passe un très faible courant stabilisé de quelques mA. Dès que le flotteur de le joug à essence change de position, le curseur de la résistance à réhostat se déplace et modifie la valeur du courant établi lorsque le véhicule était au repos. When the ignition is off, the gauge is no longer linked with the level indicator on the dashboard but with the electronic circuit of the system through which a very low stabilized current of a few mA passes. As soon as the float of the gasoline yoke changes position, the cursor of the rehostat resistance moves and modifies the value of the current established when the vehicle was at rest.

Le circuit électronique détecte cette variation de courant par un amplificateur opérationnel et déclenche alors un signal intermittent de 5 watts minimum permettant de commander un relai de puissance ou de déclencher un autre système d'alarme basé sur la détection de consommation de courant. The electronic circuit detects this variation of current by an operational amplifier and then triggers an intermittent signal of 5 watts minimum allowing to command a power relay or to trigger another alarm system based on the detection of current consumption.

Le signal s'arrête automatiquement après 30 secondes. Le système se stabilise ensuite sur la même valeur de courant ou sur une nouvelle et se trouve à nouveau prêt à déclencher 1 alarme. The signal stops automatically after 30 seconds. The system then stabilizes on the same current value or on a new one and is again ready to trigger 1 alarm.

La planche à l'appui présente le principe du dispositif où
F est le flotteur de la jauge à carburant, R la réistance, CE le circuit électronique, I l'indicateur de niveau du tableau de borc
S le signal de sortie et C la olé de contact du véhicule. The supporting board presents the principle of the device where
F is the fuel gauge float, R is the resistor, CE is the electronic circuit, I is the level indicator on the boot panel.
S the output signal and C the vehicle contact light.

Claims

1. Device intended for the protection against theft of vehicles, their wheels and their fuel, characterized in that it triggers an audible, luminous alarm Qu intermittent radio following a change in inclination of the vehicle or d '' a drop in fuel level

2. Device according to claim 1. characterized in that it is electrically inserted between the float gauge varying a resistance and the level indicator of the dashboard.

3. Device according to claim 1 characterized in that it detects a displacement of the float by variation of a very small current pass between the resistance of the gauge and the electronic circuit.

4. Device according to claim 3 characterized in that the value of this veriation can be adjustable.

5. Device according to claims 4 and 5 characterized in that the electronic circuit uses MOS oircuits and an operational amplifier.

6. Device according to claim 1 characterized in that the signal transmitted after detection is 5 watts minimum.

7. Vehicle equipped with a device according to any one of the preceding claims.